In animals, including humans, exposure to levels of illumination common in the environment has been shown to cause photoreceptor cell damage and death. Although much is known about the morphological manifestations of this light damage, there is little information about the changes that occur at the molecular level. This is especially true for the retinal ganglion cell (RGC). The work described in this proposal represents the initial steps in the adaption of an established morphological model of light-induced retinal degeneration to the study of the biochemical consequences of light damage with special emphasis on the RGC. Proteins synthesized by retinal cells with or without light damage will be labeled by making an intravitreal injection of a radioactive amino acid. The amount, types and turnover of proteins made by the whole retina and those derived from the RGCs and axonally transported within the optic nerve and tract will be analyzed using one- and two-dimensional polyacrylamide gel electrophoresis combined with fluorographic detection of the radioactive proteins. These procedures will reveal the biochemical consequences of light damage for the whole retina and will permit the documentation of changes specifically localized to th RGC. Any changes in axonally transported proteins from the RGC can be related to changes in cellular functions subserved by the membranous organelles, soluble cytoplasmic proteins or cytoskeleton. In additon, since it is known that the sensitivity of the retina to light damage is partly dependent on the hormonal status of the animal, it will be possible in future studies to explore the biochemical correlates of this hormonal dependence. Such observations will help elucidate the mechanisms by which light-induced retinopathies occur and what role hormones may play in the prevention or repair of such injury. The questions that will be addressed by this project have been identified as having high priority in the National Advisory Eye Council report, "Vision Research--A National Plan: 1978-1982." Under the section entitled, "Retinal and Choroidal Diseases," specific reference is made to promoting investigation of the biochemcial events that occur in the retina in response to illumination (p. 65) and processes that will promote regeneration of neural tissue (p. 67).